HMMT 二月 2000 · POW 赛 · 第 10 题
HMMT February 2000 — POW Round — Problem 10
题目详情
英文原题
- Find the number of distributions of a giv en set of m iden ti al balls in to a giv en set ofn distin t b o xes.
解析
英文解析
- or . This an be seen from the fa t that each distribution an be m n 1
des rib ed b y a om bination of letters, where each letter represen ts a di eren t b o x. Then um b er of times each letter o urs in the om bination is determined b y the number ofballs in the orresp onding b o x.
m ! m m m m m m
1 1 2